COMMUNICATION SYSTEM, COMMUNICATION APPARATUS, WIRELESS BASE STATION, AND WIRELESS TERMINAL STATION
A downlink data frame addressed to a terminal is copied and obtained downlink data frames are transmitted through different APs, respectively. When a plurality of same uplink data frames are received through the different APs, any one uplink data frame selected out of the uplink data frames is transmitted to its destination. An uplink data frame received from the terminal is copied and obtained uplink data frames are transmitted through different STAs, respectively. When a plurality of same downlink data frames are received through different STAs, any one downlink data frame selected out of the downlink data frames is transmitted to the terminal.
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The present invention relates to a wireless communication technology in a mobile communication network, and more particularly, to a network diversity communication that realizes a seamless handover.
BACKGROUND ARTAs a conventional technology for realizing a seamless communication (handover) of a terminal apparatus in a wireless communication system, for example, there are technologies disclosed in Patent Documents 1 and 2. In the technology disclosed in Patent Document 1, registration information of a terminal apparatus is exchanged between adjacent routers and a seamless movement of the terminal apparatus is realized by using the exchanged information. In the technology disclosed in Patent Document 2, encapsulation and decapsulation of data are performed by using a dynamically allocatable address such as an IP address to realize a seamless movement of a terminal apparatus.
Patent Document 1: Japanese Patent Application Laid-open No. 2004-533790
- Patent Document 2: Japanese Patent Application Laid-open No. 2003-244207
However, the conventional technology for realizing a seamless communication is a reference to a procedure of seamless movement from a single communication path to another single communication path and is a reference to a procedure of an access router for managing a seamless movement through an encapsulation of a network layer such as the IP. Therefore, no solution is found concerning a seamless movement of a terminal apparatus through a plurality of communication paths and a seamless movement in a wide Ethernet (registered trademark) network and the like of a data link layer that does not require a network-layer apparatus.
The present invention has been achieved in view of the above aspects and it is an object of the present invention to obtain a communication system, a communication apparatus, a wireless base station, and a wireless terminal station that realize a seamlessness communication through a plurality of communication paths and a seamless movement of a terminal apparatus in an existing network of a data link layer.
Means for Solving ProblemTo solve the above problems and to achieve the object, a communication system according to the present invention includes a plurality of wireless base stations, a first network diversity apparatus connected to the wireless base stations, and a mobile including a plurality of wireless terminal stations connected to any one of the wireless base stations by wireless and connected to a single terminal apparatus by wire and a second network diversity apparatus connected to the wireless terminal stations. The first network diversity apparatus includes a downlink-data-frame copying and transmitting unit that copies a downlink data frame addressed to the terminal apparatus and transmits downlink data frames obtained by the copying processing to the terminal apparatus through different base stations, respectively, and an uplink-data-frame selecting and transmitting unit that transmits, when a plurality of uplink data frames having same content are received through different wireless base stations, respectively, any one uplink data frame selected out of the uplink data frames to a destination thereof. The second network diversity apparatus includes an uplink-data-frame copying and transmitting unit that copies an uplink data frame received from the terminal apparatus and transmits uplink data frames obtained by the copying processing to a destination thereof through different wireless terminal stations, respectively, and a downlink-data-frame selecting and transmitting unit that transmits, when a plurality of downlink data frames having same content are received through different wireless terminal stations, respectively, any one downlink data frame selected out of the downlink data frames to the terminal apparatus.
Effect of the InventionIn a transmission operation for an uplink data frame, a communication system according to the present invention copies a data frame in an ND apparatus (a network diversity apparatus) on a mobile side. On the other hand, in transmission operation for a downlink data frame, the communication system copies a data frame in an ND apparatus on a stationary network side. The communication system transmits the same data frames (data frames including the same data) to the opposed ND apparatus via a plurality of wireless communication paths. The ND apparatus that receives a plurality of the same data frames selects one of the same data frames and delivers the selected data frame to a destination. As a result, as long as at least one wireless communication path is secured, it is possible to prevent an instantaneous breakage of data and to realize a communication system that does not cause a discomfort to a user.
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1, 2, 1a, 2a, 1b, 2b, 1c, 1d, 2d, 1e, 2e network diversity apparatuses (ND apparatuses)
- 3-1 to 3-3, 3a-1 to 3a-3, 3e-1 to 3e-3 wireless base stations (APs: Access Points)
- 4-1, 4-2, 4a-1, 4a-2, 4e-1, 4e-2 wireless terminal stations (STAs: Stations)
- 5, 6, 5e, 6e layer 2 switches (L2 switches)
- 7 server apparatus
- 8 terminal apparatus
- 101, 102 LAN receiving units
- 102, 202 LAN transmitting units
- 103, 103a, 103b, 103c, 203, 203a, 203b filter/allocating units
- 104, 104d, 104e, 204 encapsulating units
- 105, 105b, 105e, 205, 205b copying units
- 106, 206 selecting and combining units
- 107, 207 decapsulating units
- 108, 108b, 208, 208b own-MAC-address storing units
- 109, 209 transmitter-receiver-list storing units
- 110 transmitter-receiver-terminal learning unit
- 111, 211 ND-apparatus-search responding units
- 112, 212 opposed-ND-apparatus-information storing units
- 113 ND apparatus-terminal learning unit
- 114 proxy-ARP-response generating unit
- 181 own-MAC-address storage area
- 182 search-request-source-AP storage area
- 183 latest-search-time storage area
- 301 wireless receiving unit
- 302 wireless transmitting unit
- 303 wireless-connection control unit
- 304 frame generating unit
- 305 encapsulating unit
- 306 ND-apparatus-information storing unit
- 307 LAN transmitting unit
- 308 LAN receiving unit
- 309, 313 filter units
- 310 decapsulating unit
- 311 wireless-frame generating unit
- 312, 312b ND-apparatus searching units
- 314 ND-apparatus-information managing unit
- 315 ND-apparatus-information notifying unit
- 316 path-learning-packet generating unit
- 401 LAN receiving unit
- 402 LAN transmitting unit
- 403, 413 filter units
- 404 decapsulating unit
- 405 wireless-frame generating unit
- 406 wireless transmitting unit
- 407 wireless receiving unit
- 408 wireless-connection control unit
- 409 frame generating unit
- 410 encapsulating unit
- 411 ND-apparatus-information storing unit
- 412, 412b ND-apparatus searching units
- 414 remote-ND-apparatus-information managing unit
- 415 remote-ND-apparatus-information notifying unit
- 416 path-learning-packet generating unit
Embodiments of a communication system, a communication apparatus, a wireless base station, and a wireless terminal station according to the present invention are explained in detail below with reference to the drawings. The present invention is not limited by the embodiments.
First EmbodimentIn the communication system according to this embodiment, a plurality of paths are established between the ND apparatus 1 on the mobile base station side and the ND apparatus 2 on the mobile side to realize a network diversity function. In the example shown in
The APs 3-1 to 3-3 are arranged to cover a moving range of the mobile and connected to the ND apparatus 1 via the L2 switch 5. The mobile includes two sets of wireless terminal stations (STAs 4-1 and 4-2). The STAs are connected to the ND apparatus 2 via the L2 switch 6.
The copying unit 105 and the LAN transmitting unit 102 configure a downlink-data-frame copying and transmitting unit described in claims 1, 2, and 12. The selecting and combining unit 106, the decapsulating unit 107, and the LAN transmitting unit 102 configure an uplink-data-frame selecting and transmitting unit described in claims 1, 2, and 12. The transmitter-receiver-terminal learning unit 110 configures a base-station-address storing unit described in claims 5 and 13. The copying unit 205 and the LAN transmitting unit 202 configure an uplink-data-frame copying and transmitting unit described in claims 1 and 2. The selecting and combining unit 206, the decapsulating unit 207, and the LAN transmitting unit 202 configure a downlink-data-frame selecting and transmitting unit described in claims 1 and 2.
The wireless-connection control unit 303 configures a wireless-terminal-station-address storing unit described in claims 3 and 16. The encapsulating unit 305 and the LAN transmitting unit 307 configure an uplink-encapsulated-data-frame transmitting unit described in claim 3. The wireless-frame generating unit 311 and the wireless transmitting unit 302 configure a downlink-data-frame transmitting unit described in claims 3 and 17.
In
Transmission operation for traffic in an uplink direction flowing from the terminal apparatus 8 to the server apparatus 7 and transmission operation for traffic in a downlink direction flowing in the opposite direction are explained with reference to
First, the transmission operation for the traffic in the uplink direction is explained. The ND apparatus 1 recognizes the presence of the APs 3-1 to 3-3 and stores information concerning the APs (address information of the APs, etc.) in the transmitter-receiver-list storing unit 109 (see
In the ND apparatus 2 having the configuration shown in
When a data frame (an un-encapsulated data frame) is received from the filter/allocating unit 203, the encapsulating unit 204 encapsulates the data frame. The encapsulating unit 204 sets an MAC address of the own apparatus (the ND apparatus 2), which is information stored by the own-MAC-address storing unit 208, as a source address (equivalent to Step S11 in
The copying unit 205 copies an encapsulated frame, which is the data frame encapsulated by the encapsulating unit 204, and sets destinations of the encapsulated data frame in the STA 4-1 and the STA 4-2 using information (MAC addresses of the STAs) stored by the transmitter-receiver-list storing unit 209 (equivalent to Step S12 in
In the STA 4-1 and the STA 4-2 having the configuration shown in
In the APs 3-1 to 3-3 having the configuration shown in
Address information of the STA as a transmitter and address information of the terminal apparatus 8 as a traffic source are passed from the wireless receiving unit 301 to the wireless-connection control unit 303. The wireless-connection control unit 303 stores the received address information of the STA and address information of the terminal apparatus 8 in association with each other and prepares for transmission operation for traffic in the opposite direction (downlink traffic).
The frame generating unit 304 removes a header section of the received wireless data frame and passes the wireless data frame to the encapsulating unit 305. The encapsulating unit 305 encapsulates the data frame received from the frame generating unit 304, acquires information (MAC address information of the ND apparatus 1) stored by the ND-apparatus-information storing unit 306, and sets the information as a destination address of the encapsulated data frame (equivalent to Step S14 in
In the ND apparatus 1 having the configuration shown in
Address information of the AP as a transmitter and address information of the terminal apparatus 8 as a traffic source are passed from the selecting and combining unit 106 to the transmitter-receiver-terminal learning unit 110. The transmitter-receiver-terminal learning unit 110 stores the received address information of the AP and address information of the terminal apparatus 8 in association with each other and prepares for transmitting operation for traffic in the opposite direction (downlink traffic). An AP that communicates with an STA connected to the terminal apparatus 8 according to the elapse of time (according to the movement of the mobile in which the terminal apparatus 8 is disposed). Therefore, at this point, an AP through which data frame is exchanged with the terminal apparatus 8 is stored.
When encapsulated data frames including the same data (hereinafter simply referred to as same frames) are received from the AP 3-1 and the AP 3-2, the selecting and combining unit 106 selects one of the same frames and passes the frame to the decapsulating unit 107 (equivalent to Step S15 in
Transmitting operation for traffic in a downlink direction is explained. The STAs 4-1 and 4-2 recognize the presence of the ND apparatus 2 and store ND apparatus information in the ND-apparatus-information storing unit 411.
In the ND apparatus 1 having the configuration shown in
When a data frame (an un-encapsulated data frame) is received from the filter/allocating unit 103, the encapsulating unit 104 encapsulates the data frame. The encapsulating unit 104 sets an MAC address of an own apparatus (the ND apparatus 1), which is information stored by the own-MAC-address storing unit 108, as a source address (equivalent to Step S21 in
The copying unit copies the encapsulated data frames, which are the data frames encapsulated by the encapsulating unit 104, and sets destinations of the encapsulated data frames to the AP 3-1 and the AP 3-2 (equivalent to Step S22 in
In the APs 3-1 to 3-3 having the configuration shown in
In the STA 4-1 and the STA 4-2 shown in
The frame generating unit 409 removes a header section of the received wireless data frame and passes the wireless data frame to the encapsulating unit 410. The encapsulating unit 410 encapsulates the data frame received from the frame generating unit 409, acquires information (MAC address information of the ND apparatus 2) stored by the ND-apparatus-information storing unit 411, and sets the information as a destination address of an encapsulated data frame (equivalent to Step S24 in
In the ND apparatus 2 having the configuration shown in
When the same frames are received from the STA 4-1 and the STA 4-2, the selecting and combining unit 206 selects one of the received same frames and passes the frame to the decapsulating unit 207 (equivalent to Step S25 in
In this embodiment, the two sets of APs and STAs simultaneously perform wireless connection and transmit the two same frames in parallel. However, the present invention is not limited to this. Three or more sets of APs and STAs can simultaneously perform wireless connection and transmit a number of same frames corresponding to the number of wireless connections in parallel.
As explained above, in this embodiment, in the transmitting operation for an uplink data frame, a data frame is copied by the ND apparatus on the mobile side and, on the other hand, in the transmitting operation for a downlink data frame, a data frame is copied by the ND apparatus on the stationary network side, the same data frames (data frames including the same data) are transmitted to the opposed ND apparatuses via a plurality of wireless communication paths, and the ND apparatus that receives a plurality of the same data frames select one of the data frames and delivers the data frame to a destination. Consequently, it is possible to prevent data short break if at least one wireless communication path is secured and to realize a communication system that does not give discomfort to a user.
Because the AP and the STA transmit only an encapsulated data frame among frames received by the LAN receiving units, an intra-system wire communication section can be realized by only the standard L2 switching operation of the L2 switch by always using an encapsulated frame for communication between the ND apparatus and the AP and between the ND apparatus and the STA. Therefore, it is possible to realize the communication system according to the present invention by connecting the ND apparatus and the AP and the STA using an existing network.
Further, in a generation source of traffic and an apparatus that performs traffic termination, communication can be realized by transmission and reception of a standard Ethernet (registered trademark) frame. Therefore, it is possible to realize seamless communication even when a commercially available apparatus is connected to the communication system according to the present invention.
Second EmbodimentA communication system according to a second embodiment is explained. In the first embodiment, the AP and the STA recognize the presence of the near ND apparatus and uniquely designate a destination in encapsulation. An embodiment in which an AP and an STA search for a near AD apparatus with the same system configuration (see
As shown in
The ND-apparatus searching unit 312 configures a first network-diversity-apparatus searching unit described in claim 4 and a network-diversity-apparatus searching unit described in claim 18. The wireless-connection control unit 303 configures a wireless-terminal-station-address storing unit described in claims 4 and 18. The encapsulating unit 305 and the LAN transmitting unit 307 configure an uplink-encapsulated-data-frame transmitting unit described in claims 4 and 18. The wireless-frame generating unit 311 and the wireless transmitting unit 302 configure a downlink-encapsulated-data-frame transmitting unit described in claims 4 and 18.
The ND-apparatus searching unit 412 configures a second network-diversity-apparatus searching unit described in claim 4 and a network-diversity-apparatus searching unit described in claim 19. The encapsulating unit 410 and the LAN transmitting unit 402 configure a downlink-encapsulated-data-frame transmitting unit described in claims 4 and 19.
A procedure of the AP 3a (the AP 3a-1 to the AP 3a-3) and the STA 4a (the STA 4a-1 and the STA 4a-2) for searching for an ND apparatus is explained with reference to
First, a procedure of the AP 3a for searching for an ND apparatus is explained. When the AP 3a is started, the AP 3a generates the ND apparatus search request frame F31 in the ND-apparatus searching unit 312 and passes the frame to the LAN transmitting unit 307. The LAN transmitting unit 307 broadcast-transmits the received frame.
When the ND apparatus 1a having the configuration shown in
The ND-apparatus-search responding unit 111 passes information concerning the AP 3a, which is a transmission source of the received ND apparatus search request frame, to the transmitter-receiver-list storing unit 109, generates the ND apparatus search response frame F32 (see
In the AP 3a, the LAN receiving unit 308 receives frames. A filter unit 309a extracts an ND apparatus search response frame out of the frames received by the LAN receiving unit 308 and passes the ND apparatus search response frame to the ND-apparatus searching unit 312. The ND-apparatus searching unit 312 stores information concerning the ND apparatus 1a at the transmission source of the ND apparatus search response until the AP 3a finishes operation. In the traffic transmitting operation in the uplink direction explained in the first embodiment, the ND-apparatus searching unit 312 provides the encapsulating unit 305 with the information in the same manner as the ND-apparatus-information storing unit 306 included in the AP according to the first embodiment.
A procedure of the STA 4a for searching for an ND apparatus is explained. When the STA 4a is started, the ND-apparatus searching unit 412 of the STA 4a performs operation same as that of the ND-apparatus searching unit 312 of the AP 3a explained above and generates the ND apparatus search request frame F31. The generated ND apparatus search request frame F31 is passed to the LAN transmitting unit 402 and broadcast-transmitted.
When the NM apparatus search request frame F31 broadcast-transmitted from the STA 4a is received, the ND apparatus 2a shown in
The ND-apparatus searching unit 412 of the STA 4a stores information concerning the ND apparatus 2a in the same manner as the ND-apparatus searching unit 312 of the AP 3a and, in the traffic transmitting operation in the downlink direction explained in the first embodiment, provides the encapsulating unit 410 with the information in the same manner as the ND-apparatus-information storing unit 411 included in the STA according to the first embodiment.
The traffic transmitting operation in the uplink direction and the traffic transmitting operation in the downlink direction are the same as those in the first embodiment explained above.
In this way, in this embodiment, the AP and the STA search for a near ND apparatus and stores information concerning the ND apparatus to be connected. The ND apparatus stores information concerning the AP or the STA that performs ND apparatus search. Consequently, in addition to the effect of the first embodiment, it is possible to realize the communication system according to the present invention without performing prior setting of stored information simply by connecting the ND apparatus and the AP and the STA to the existing network.
Third EmbodimentA communication system according to a third embodiment is explained. In the first and second embodiments, the encapsulated frame is transmitted and received between the ND apparatus and the AP and between the ND apparatus and the STA. An embodiment in which ND apparatuses including a wireless section transmit and receive an encapsulated frame with the system configuration (see
As shown in
The copying unit 105b and the LAN transmitting unit 102 configure a downlink-data-frame copying and transmitting unit described in claim 7. The selecting and combining unit 106, the decapsulating unit 107, and the LAN transmitting unit 102 configure an uplink-data-frame selecting and transmitting unit described in claim 7.
As shown in
The copying unit 205b and the LAN transmitting unit 202 configure an uplink-data-frame copying and transmitting unit described in claim 7. The selecting and combining unit 206, the decapsulating unit 207, and the LAN transmitting unit 202 configure a downlink-data-frame selecting and transmitting unit described in claim 7.
The ND-apparatus searching unit 312b configures a first network-diversity-apparatus searching unit and a first address-information exchanging unit described in claim 9. The ND-apparatus-information notifying unit 315 configures a first address-information notifying unit described in claims 9 and 10.
The ND-apparatus searching unit 412b configures a second network-diversity-apparatus searching unit and a second address-information exchanging unit described in claims 9 and 10. The ND-apparatus-information notifying unit 415 configures a second address-information notifying unit described in claims 9 and 10.
A procedure of the AP 3b (the AP 3b-1 to the AP 3b-3) and the STA 4b (the STAs 4b-1 and 4b-2) for searching for an ND apparatus is explained with reference to
First, a procedure of the AP 3b for searching for an ND apparatus is explained. The AP 3b executes a procedure same as the procedure of the AP 3a according to the second embodiment, generates the ND apparatus search request frame F31 (equivalent to “near ND search request” shown in
The ND apparatus 1b that receives the ND apparatus search request frame F31 generates the ND apparatus search response frame F32 (equivalent to “near ND search response” shown in
Operation of the ND-apparatus-search responding unit 111 in acquiring information from the own-MAC-address storing unit 108b is explained with reference to
When all own MAC addresses are in use (No at Step S33), the own-MAC-address storing unit 108b selects an own MAC address used earliest and returns the selected own MAC address to the ND-apparatus-search responding unit 111 (Step S35). In this case, the own-MAC-address storing unit 108b also executes Step S6 and stores request source AP information in the search-request-source-AP storage area 182.
The own-MAC-address storing unit 108b updates information in the latest-search-time storage area 183 corresponding to the own MAC address returned to the ND-apparatus-search responding unit 111 with the present time (stores information concerning the present time in a corresponding area of the latest-search-time storage area 183) (Step S37).
The AP 3b that receives the ND apparatus search response frame F32, which is a response to the transmission of the ND apparatus search request frame F31, stores information (MAC address information) concerning the ND apparatus 1b included in the ND apparatus search response frame F32 in the ND-apparatus searching unit 312b in the same manner as the AP 3a.
A procedure of the STA 4b for searching for an ND apparatus is explained. The STA 4b executes a procedure same as the procedure of the STA 4a according to the second embodiment explained above and transmits the ND apparatus search request frame F31.
The ND apparatus 2b selects one of own MAC addresses and transmits the own MAC address with the ND apparatus search response frame F32 in a procedure same as the procedure of the ND apparatus 1b.
The STA 4b stores information concerning the ND apparatus 2b included in the ND apparatus search response frame F32 in the ND-apparatus searching unit 412b in the same manner as the STA 4a.
A procedure of the AP 3b and the STA 4b for exchanging remote ND apparatus information and notifying a near ND apparatus of the remote ND apparatus information is explained with reference to
When a wireless link is established, the AP 3b and the STA 4b notify of each other of ND apparatus information stored in the ND-apparatus searching unit 312b and the ND-apparatus searching unit 412b, respectively (equivalent to “ND information exchange” shown in
The AP 3b stores the information concerning the ND apparatus 2b notified from the STA 4b in the remote-ND-apparatus-information managing unit 314. The AP 3b generates a remote ND apparatus notification message (equivalent to “remote ND notification” shown in
When the remote ND apparatus notification message is received from the AP 3b, the ND apparatus 1b stores the notified information in the opposed-ND-apparatus-information storing unit 112.
As in the processing of the AP 3b, the STA 4b stores the information concerning the ND apparatus 1b notified from the AP 3b in the remote-ND-apparatus-information managing unit 414. The STA 4b generates a remote ND apparatus notification message (equivalent to “remote ND notification” shown in
When the remote ND apparatus notification message is received from the STA 4b, the ND apparatus 2b stores the notified information in the opposed-ND-apparatus-information storing unit 212.
Transmitting operation for traffic in an uplink direction flowing from the terminal apparatus 8 to the server apparatus 7 is explained. In the ND apparatus 2b, the encapsulating unit 204 encapsulates the data frame F41 and passes the data frame F41 to the copying unit 205b. The copying unit 205b copies the received encapsulated data frame, acquires information stored by the own-MAC-address storing unit 208b, and sets two own MAC addresses (M1_ND2b and M2_ND2b) as transmission source addresses of the encapsulated data frames. The copying unit 205b generates F42-1 and F42-2 by setting destination in two MAC addresses (M1_ND1b and M2_ND1b) of the remote ND apparatus 1b using information stored by the opposed-ND-apparatus-information storing unit 212.
One of the encapsulated frames is delivered to the STA 4b-1 from the L2 switch 6 according to a path learning result. The encapsulated frame F42-1 is delivered to the STA 4b-1. The STA 4b-1 does not decapsulate the received encapsulated frame and generates the wireless data frame F43-1 and transmits the wireless data frame F43-1 to the AP 3b-1 under connection.
On the other hand, one of the encapsulated frames is also delivered to the STA 4b-2 from the L2 switch 6 according to the path learning result. The STA 4b-2 does not decapsulate the received encapsulated frame and generates the wireless data frame F43-2 and transmits the wireless data frame F43-2 to the AP 3b-2.
The AP 3b generates an Ethernet (registered trademark) frame from a data frame received by the wireless receiving unit 301 and transmits the Ethernet frame to the ND apparatus 1b. The AP 3b does not encapsulate the frame.
The ND apparatus 1b selects one of the same frames received from the APs 3b-1 and 3b-2 in the selecting and combining unit 106 and passes the same frame to the decapsulating unit 107. The decapsulating unit 107 removes an encapsulated header from the received encapsulated data frame and transmits the data frame to the server apparatus 7.
One of MAC addresses of the ND apparatus 2b as transmission source information and address information of the terminal apparatus 8 as a traffic source are passed from the selecting and combining unit 106 to the ND-apparatus-terminal learning unit 113. the ND-apparatus-terminal learning unit 113 stores the received MAC address information of the ND apparatus 2b and address information of the terminal apparatus 8 in association with each other and prepares for transmitting operation for traffic in the opposite direction (downlink traffic).
Transmitting operation for traffic in a downlink direction flowing from the server apparatus 7 and the terminal apparatus 8 is substantially the same as the transmitting operation for the traffic in the uplink direction explained above. However, in the ND apparatus 1b, the transmitting operation is different in that the copying unit 105b acquires information stored by the ND-apparatus-terminal learning unit 113 using the address information of the terminal apparatus 8 as a key and determines a destination address of an encapsulated data frame using the acquired information. Operation of the copying unit 105b for determining a destination address is the same as the procedure of the copying unit 105 for acquiring address information of the AP 3-1 and address information of the AP 3-2 explained in the first embodiment.
As explained above, in this embodiment, a result of the search for a near ND apparatus performed by the AP and the STA is notified to the opposed remote ND apparatus via the wireless link, the L2 switch is caused to learn an MAC address of the remote ND apparatus, and termination of an encapsulated data frame is performed by only the ND apparatus. Consequently, in addition to the effects of the first and second embodiments, it is possible to reduce a transmission delay involved in encapsulation processing and decapsulation processing in the communication system.
Fourth EmbodimentA communication system according to the fourth embodiment is explained. In the first to third embodiments, all the data frames transmitted by the server apparatus 7 are transmitted to the terminal apparatus 8. An embodiment in which an ND apparatus responds as a proxy of a terminal apparatus concerning an ARP request frame among data frames with the same system configuration as the first embodiment is explained below.
A procedure of the ND apparatus 1c for responding as an ARP proxy is explained. When an ARP request frame is received, the filter/allocating unit 103c of the ND apparatus 1c allocates the frame to the proxy-ARP-response generating unit 114. When a frame other than the ARP request frame is received, the filter/allocating unit 103c performs operation same as the operation of the filter/allocating unit 103 according to the first embodiment.
When the ARP request frame is received, the proxy-ARP-response generating unit 114 inquires the transmitter-receiver-terminal learning unit 110 whether a resolution target address of the ARP request frame is included in learning content of the transmitter-receiver-terminal learning unit 110. When the ARP request frame is an MAC address inquiry of the terminal apparatus 8, because the transmitter-receiver-terminal learning unit 110 stores MAC address information, the proxy-ARP-response generating unit 114 generates an ARP response frame using the information.
In the example explained in this embodiment, the ND apparatus according to the first embodiment includes the filter/allocating unit 103c and the proxy-ARP-response generating unit 114. However, the present invention is not limited to this. The ND apparatuses according to the second and third embodiment can include the filter/allocating unit 103c and the proxy-ARP-response generating unit 114.
As explained above, in this embodiment, the ND apparatus responds to the ARP request frame as a proxy to prevent a multicast frame being transmitted in a wireless communication section. Consequently, in addition to the effects of the first to third embodiments, it is possible to reduce transmission load in the communication system.
Fifth EmbodimentA communication system according to a fifth embodiment is explained. In the first to fourth embodiments, the operation of the ND apparatus for copying a data frame and delivering data frames to the transmitter and the receiver (the AP and the STA) frame by frame is explained. An embodiment in which a data frame is not copied and a plurality of APs or STAs are caused to deliver an encapsulated data frame in one transmission is explained below.
An operation of the ND apparatus 1d for transmitting an uplink data frame to the AP 3-1 and the AP 3-2 in transmitting operation for traffic in a downlink direction flowing from the server apparatus 7 to the terminal apparatus 8 is explained. The ND apparatus 1d recognizes an address of a multicast group to which the APs 3-1 and 3-2 belong. The encapsulating unit 104d stores information concerning the address. The L2 switch 5 recognizes the address of the multicast group to which the APs 3-1 and 3-2 belong and has ability for allocating frames according to the information concerning the address.
In the ND apparatus 1d, the encapsulating unit 104 encapsulates the data frame F51 received from the server apparatus 7 and sets a transmission source address using information stored by the own-MAC-address storing unit 108. The encapsulating unit 104 generates the encapsulated data frame F52 with a destination address set to the address of the multicast group to which the APs 3-1 and 3-2 belong. The generated encapsulated data frame F52 is transmitted from the LAN transmitting unit 102.
The L2 switch 5 transfers the encapsulated data frame F52 to the APs 3-1 and 3-2 belonging to the multicast group according to destination address information of the encapsulated data frame F52 transmitted from the ND apparatus 1d.
Operation after the encapsulated data frame F52 reaches the APs 3-1 and 3-2 is the same as the operation in the first embodiment explained above.
For transmitting operation for traffic in an uplink direction flowing from the terminal apparatus 8 to the server apparatus 7, the multicast address can also be used concerning encapsulated data transfer between the ND apparatus disposed in the mobile and the STAs 4-1 and 4-2.
When the ND apparatuses according to the second to fourth embodiments encapsulate a data frame, the multicast address can be set as a destination address of the data frame.
As explained above, in this embodiment, the ND apparatus does not copy a data frame. The multicast address is used for destination information of an encapsulated frame. The ND apparatus only has to transmit an encapsulated data frame once. Consequently, in addition to the effects of the first to fourth embodiments, it is possible to reduce transmission load of the ND apparatus.
Sixth EmbodimentA communication system according to a sixth embodiment is explained. In the third embodiment explained above, each of the ND apparatuses has two MAC addresses. The operation for properly using the MAC addresses according to a communication path is explained. An embodiment in which the MAC addresses of each of ND apparatuses are reduced to one MAC address but, instead, a communication path is properly used by using a VLAN (Virtual LAN) is explained.
The copying unit 105e and the LAN transmitting unit 102 configure an uplink-data-frame copying and transmitting unit and a downlink-data-frame copying and transmitting unit described in claim 8, a downlink-data-frame copying and transmitting unit described in claim 15, and an uplink-data-frame copying and transmitting unit described in claim 16. The selecting and combining unit 106, the decapsulating unit 107, and the LAN transmitting unit 102 configure an uplink-data-frame selecting and transmitting unit and a downlink-data-frame selecting and transmitting unit described in claim 8, a downlink-data-frame selecting and transmitting unit described in claim 15, and an uplink-data-frame selecting and transmitting unit described in claim 16.
Transmitting operation for traffic in an uplink direction flowing from the terminal apparatus 8 to the server apparatus 7 is explained.
The L2 switch 5e recognizes for which of a plurality of communication paths the connected APs 3e-1 to 3e-3 are used and recognizes a VLAN identifier for each of the paths. For example, in the system according to this embodiment (see
In the ND apparatus disposed in the mobile, the encapsulating unit 104e encapsulates the data frame F61 received from the terminal apparatus 8. The copying unit 105e copies the encapsulated data frame and sets own MAC addresses as transmission source addresses of the encapsulated data frames suing information stored by the own-MAC-address storing unit 108. The copying unit 105e sets an MAC address of the ND apparatus 1e which is a remote ND apparatus, as a destination address using information stored by the opposed-ND-apparatus-information storing unit 112. The copying unit 105e sets values peculiar to two paths in VLAN identifier areas of encapsulated headers to thereby generate encapsulated data frames F62-1 and F62-2. The generated encapsulated data frames F62-1 to F62-2 are transmitted from the LAN transmitting unit 102.
The L2 switch 6e allocates encapsulated data frames received from the ND apparatus 2e according to VLAN identifiers of the encapsulated data frames. Specifically, the encapsulated data frame F62-1 is passed to the STA 4e-1 and the encapsulated data frame F62-2 is passed to the STA 4e-2.
For transmitting operation for traffic in a downlink direction flowing from the server apparatus 7 to the terminal apparatus 8, transmission paths can be identified according to VLAN identifiers in the same manner.
As explained above, in this embodiment, communication paths are properly used according to VLAN identifiers. Consequently, even if there is only one MAC address allocated to the ND apparatuses, it is possible to obtain the same effect as the third embodiment.
Seventh EmbodimentA communication system according to a seventh embodiment is explained. In the first to sixth embodiments, network diversity operation in the system configuration in which the mobile includes a plurality of STAs is explained. However, the communication system can have a system configuration in which a single STA performs communication with a plurality of APs by, for example, sharing the same change in a time division manner according to CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) or the like.
In the first to sixth embodiments, the communication system in which the ND apparatus and the L2 switch on the mobile side are independent is explained. However, an ND apparatus can also perform the L2 switch function, whereby an STA and the ND apparatus are integrated.
As explained above, in this embodiment, a single STA is allowed to independently communicate with a plurality of APS by time division or the like. Therefore, it is possible to obtain the same effect as the embodiments explained above simply by arranging the single STA in the mobile. An ND apparatus also having the L2 switch function is used to integrate an STA and the ND apparatus. Therefore, it is possible to obtain the same effect as the embodiments by arranging an only apparatus (an apparatus obtained by integrating the STA and the ND apparatus) in the mobile.
INDUSTRIAL APPLICABILITYAs explained above, the communication system, the communication apparatus, the wireless base station, and the wireless terminal station according to the present invention is suitable for realizing seamless communication using network diversity communication.
Claims
1-19. (canceled)
20: A communication system including a plurality of wireless base stations, a first network diversity apparatus connected to the wireless base stations, and a mobile including a plurality of wireless terminal stations connected to any one of the wireless base stations by wireless and connected to a single terminal apparatus by wire and a second network diversity apparatus connected to the wireless terminal stations, wherein
- the first network diversity apparatus includes a downlink-data-frame copying and transmitting unit that copies a downlink data frame addressed to the terminal apparatus and transmits downlink data frames obtained by the copying processing to the terminal apparatus through different base stations, respectively, and an uplink-data-frame selecting and transmitting unit that transmits, when a plurality of uplink data frames having same content are received through different wireless base stations, respectively, any one uplink data frame selected out of the uplink data frames to a destination thereof, and
- the second network diversity apparatus includes an uplink-data-frame copying and transmitting unit that copies an uplink data frame received from the terminal apparatus and transmits uplink data frames obtained by the copying processing to a destination thereof through different wireless terminal stations, respectively, and a downlink-data-frame selecting and transmitting unit that transmits, when a plurality of downlink data frames having same content are received through different wireless terminal stations, respectively, any one downlink data frame selected out of the downlink data frames to the terminal apparatus.
21: A communication system including a plurality of wireless base stations, a first network diversity apparatus connected to the wireless base stations, and a mobile including a plurality of wireless terminal stations connected to any one of the wireless base stations by wireless and connected to a single terminal apparatus by wire and a second network diversity apparatus connected to the wireless terminal stations, wherein
- the first network diversity apparatus includes a downlink-data-frame copying and transmitting unit that copies a downlink encapsulated data frame generated by encapsulating a downlink data frame addressed to the terminal apparatus and transmits downlink encapsulated data frames obtained by executing the copying processing to the second network diversity apparatus through different base stations, respectively, and an uplink-data-frame selecting and transmitting unit that decapsulates, when a plurality of uplink encapsulated data frames having same content are received through different wireless base stations, respectively, any one uplink encapsulated data frame selected out of the uplink encapsulated data frames and transmits obtained uplink data frame to a destination thereof, and
- the second network diversity apparatus includes an uplink-data-frame copying and transmitting unit that copies an uplink encapsulated data frame generated by encapsulating an uplink data frame received from the terminal apparatus and transmits uplink encapsulated data frames obtained by executing the copying processing to the first network diversity apparatus through different wireless terminal stations, respectively, and a downlink-data-frame selecting and transmitting unit that transmits, when a plurality of downlink encapsulated data frames having same content are received through different wireless terminal stations, respectively, any one downlink encapsulated data frame selected out of the downlink encapsulated data frames to the terminal apparatus.
22: The communication system according to claim 21, wherein
- the wireless base station includes a wireless-terminal-station-address storing unit that stores address information of a transmission source terminal apparatus included in an uplink wireless data frame generated and transmitted by the wireless terminal station and address information of the wireless terminal station in association with each other, an uplink-encapsulated-data-frame transmitting unit that transmits an uplink encapsulated data frame generated based on the uplink wireless data frame to the first network diversity apparatus, and a downlink-wireless-data-frame transmitting unit that transmits a downlink wireless data frame generated based on a downlink encapsulated data frame generated and transmitted by the first network diversity apparatus to a transmission destination wireless terminal station determined based on address information of a destination terminal apparatus included in the downlink encapsulated data frame and information stored by the wireless-terminal-station-address storing unit, and
- the wireless terminal station includes a downlink-encapsulated-data-frame transmitting unit that transmits a downlink encapsulated data frame generated based on a downlink wireless data frame received from the wireless base station to the second network diversity apparatus, and an uplink-wireless-data-frame transmitting unit that transmits an uplink wireless data frame generated based on an uplink encapsulated data frame received from the second network diversity apparatus to a wireless base station under connection.
23: The communication system according to claim 21, wherein
- the wireless base station includes a first network-diversity-apparatus searching unit that broadcast-transmits, when the own station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame, a wireless-terminal-station-address storing unit that stores address information of a transmission source terminal apparatus included in an uplink wireless data frame generated and transmitted by the wireless terminal station and address information of the wireless terminal station in association with each other, an uplink-encapsulated-data-frame transmitting unit that sets address information stored by the first network-diversity-apparatus searching unit as a destination address of an uplink encapsulated data frame generated based on the uplink wireless data frame generated and transmitted by the wireless terminal station and transmits the uplink encapsulated data frame to a destination thereof, and a downlink-wireless-data-frame transmitting unit that transmits a downlink wireless data frame generated based on a downlink encapsulated data frame received from the first network diversity apparatus to a transmission destination wireless terminal station determined based on address information of a destination terminal apparatus included in the downlink encapsulated data frame and information stored by the wireless-terminal-station-address storing unit, and
- the wireless terminal station includes a second network-diversity-apparatus searching unit that broadcast-transmits, when the own station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame, a downlink-encapsulated-data-frame transmitting unit that sets address information stored by the second network-diversity-apparatus searching unit as a destination address of a downlink encapsulated data frame generated based on a downlink wireless data frame received from the wireless base station and transmits the downlink encapsulated data frame, and an uplink-wireless-data-frame transmitting unit that transmits an uplink wireless data frame generated based on an uplink encapsulated data frame received from the second network diversity apparatus to a wireless base station under connection.
24: The communication system according to claim 21, wherein
- the first network diversity apparatus further includes a base-station-address storing unit that stores address information of a transmission source terminal apparatus included in an uplink data frame obtained by executing the decapsulation processing and address information of a wireless base station that transmits the uplink encapsulated data frame, and
- the downlink-data-frame copying and transmitting unit determines, when a downlink encapsulated data frame is copied, a destination address set in copied downlink encapsulated data frame based on a destination address of the downlink data frame and information stored by the base-station-address storing unit.
25: The communication system according to claim 24, wherein the first network diversity apparatus further includes an ARP-response-packet generating unit that generates, when an address resolution protocol packet for performing path learning is received, a response packet to the address resolution protocol packet on behalf of a wireless base station connected to the first network diversity apparatus based on information stored by the base-station-address storing unit.
26: The communication system according to claim 21, wherein
- the downlink-data-frame copying and transmitting unit does not copy the downlink encapsulated data frame, sets a multicast address, which is used during multicast transmission to a wireless base station connected to the first network diversity apparatus, as a destination address of the downlink encapsulated data frame, and transmits the downlink encapsulated data frame, and
- the uplink-data-frame copying transmitting unit does not copy the uplink encapsulated data frame, sets a multicast address, which is used during multicast transmission to a wireless terminal station connected to the second network diversity apparatus, as a destination address of the uplink encapsulated data frame, and transmits the uplink encapsulated data frame.
27: A communication system including a plurality of wireless base stations, a first network diversity apparatus connected to the wireless base stations, and a mobile including a plurality of wireless terminal stations connected to any one of the wireless base stations by wireless and connected to a single terminal apparatus by wire and a second network diversity apparatus connected to the wireless terminal stations, wherein
- the first network diversity apparatus includes a downlink-data-frame copying and transmitting unit that copies a downlink encapsulated data frame generated by encapsulating a downlink data frame addressed to the terminal apparatus, sets any ones of a plurality of media access control addresses, which are allocated to the first network diversity apparatus, as source addresses of downlink encapsulated data frames obtained by executing the copying processing such that the media access control addresses do not overlap each other, sets any ones of a plurality of media access control addresses, which are acquired in advance and allocated to the second network diversity apparatus, as destination addresses of the downlink data frame such that the media access control addresses do not overlap each other, and transmits the downlink encapsulated data frames through different wireless base stations, respectively, and an uplink-data-frame selecting and transmitting unit that selects, when a plurality of uplink encapsulated data frames having same content are received through different wireless base stations, respectively, any one of the received uplink encapsulated data frames and transmits an uplink data frame generated by decapsulating selected uplink encapsulated data frame to a destination thereof, and
- the second network diversity apparatus includes an uplink-data-frame copying and transmitting unit that copies an uplink encapsulated data frame generated by encapsulating an uplink data frame received from the terminal apparatus, sets any ones of a plurality of media access control addresses, which are allocated to the second network diversity apparatus, as source addresses of uplink encapsulated data frames obtained by executing the copying processing such that the media access control addresses do not overlap each other, sets any ones of a plurality of media access control addresses, which are acquired in advance and allocated to the first network diversity apparatus, as destination addresses of the uplink data frames such that the media access control addresses do not overlap each other, and transmits the uplink encapsulated data frames through the different wireless terminal stations, respectively, and a downlink-data-frame selecting and transmitting unit that selects, when a plurality of downlink encapsulated data frames having same content are received through different wireless terminal stations, respectively, any one of the received downlink encapsulated data frames and transmits a downlink data frame generated by decapsulating selected downlink encapsulated data frame to a destination thereof.
28: The communication system according to claim 27, wherein
- the wireless base station includes a first network-diversity-apparatus searching unit that broadcast-transmits, when the own station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame, a first address-information exchanging unit that notifies, when a link is established between the wireless base station and a wireless terminal station, the wireless terminal station of the address information stored by the first network-diversity-apparatus searching unit and acquires address information of a network diversity apparatus connected to the wireless terminal station from the wireless terminal station, and a first address-information notifying unit that notifies a network diversity apparatus connected to the wireless base station of the address information of the network diversity apparatus connected to the wireless terminal station acquired by the first address-information exchanging unit,
- the wireless terminal station includes a second network-diversity-apparatus searching unit that broadcast-transmits, when the own station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame, a second address-information exchanging unit that notifies, when a link is established between the wireless terminal station and a wireless base station, the wireless base station of the address information stored by the second network-diversity-apparatus searching unit and acquires address information of a network diversity apparatus connected to the wireless base station from the wireless base station, and a second address-information notifying unit that notifies a network diversity apparatus connected to the wireless terminal station of the address information of the network diversity apparatus connected to the wireless base station acquired by the second address-information exchanging unit, and
- the downlink-data-frame copying and transmitting unit sets the address information, which is notified from the first address-information notifying unit, as a destination address of the downlink encapsulated data frame, and the uplink-data-frame copying and transmitting unit sets the address information, which is notified from the second address-information notifying unit, as a destination address of the uplink encapsulated data frame.
29: The communication system according to claim 27, wherein
- the downlink-data-frame copying and transmitting unit does not copy the downlink encapsulated data frame, sets a multicast address, which is used during multicast transmission to a wireless base station connected to the first network diversity apparatus, as a destination address of the downlink encapsulated data frame, and transmits the downlink encapsulated data frame, and
- the uplink-data-frame copying transmitting unit does not copy the uplink encapsulated data frame, sets a multicast address, which is used during multicast transmission to a wireless terminal station connected to the second network diversity apparatus, as a destination address of the uplink encapsulated data frame, and transmits the uplink encapsulated data frame.
30: A communication system including a plurality of wireless base stations, a first network diversity apparatus connected to the wireless base stations, and a mobile including a plurality of wireless terminal stations connected to any one of the wireless base stations by wireless and connected to a single terminal apparatus by wire and a second network diversity apparatus connected to the wireless terminal stations, wherein
- the first network diversity apparatus includes a downlink-data-frame copying and transmitting unit that copies a downlink encapsulated data frame generated by encapsulating a downlink data frame addressed to the terminal apparatus, sets media access control addresses, which are acquired in advance and allocated to the second network diversity apparatus, as destination addresses of downlink encapsulated data frames obtained by executing the copying processing, sets virtual local area network identifiers of wireless base stations, which are acquired in advance, in the downlink encapsulated data frames such that the downlink encapsulated data frames are transmitted to different wireless base stations, respectively, and transmits the downlink encapsulated data frames, and an uplink-data-frame selecting and transmitting unit that selects, when a plurality of uplink encapsulated data frames having same content are received through different wireless base stations, respectively, any one of received uplink encapsulated data frames and transmits an uplink data frame generated by decapsulating selected uplink encapsulated data frame to a destination thereof, and
- the second network diversity apparatus includes an uplink-data-frame copying and transmitting unit that copies an uplink encapsulated data frame generated by encapsulating an uplink data frame received from the terminal apparatus, sets media access control addresses, which are acquired in advance and allocated to the first network diversity apparatus, as destination addresses of uplink encapsulated data frames obtained by executing the copying processing, sets virtual local area network identifiers of wireless terminal stations, which are acquired in advance, in the uplink encapsulated data frames such that the uplink encapsulated data frames are transmitted to different wireless terminal stations, respectively, and transmits the uplink encapsulated data frames, and a downlink-data-frame selecting and transmitting unit that selects, when a plurality of downlink encapsulated data frames having same content are received through different wireless terminal stations, respectively, any one of received downlink encapsulated data frames and transmits a downlink data frame generated by decapsulating the selected downlink encapsulated data frame to a destination thereof.
31: The communication system according to claim 30, wherein
- the wireless base station includes a first network-diversity-apparatus searching unit that broadcast-transmits, when the own station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame, a first address-information exchanging unit that notifies, when a link is established between the wireless base station and a wireless terminal station, the wireless terminal station of the address information stored by the first network-diversity-apparatus searching unit and acquires address information of a network diversity apparatus connected to the wireless terminal station from the wireless terminal station, and a first address-information notifying unit that notifies a network diversity apparatus connected to the wireless base station of the address information of the network diversity apparatus connected to the wireless terminal station acquired by the first address-information exchanging unit,
- the wireless terminal station includes a second network-diversity-apparatus searching unit that broadcast-transmits, when the own station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame, a second address-information exchanging unit that notifies, when a link is established between the wireless terminal station and a wireless base station, the wireless base station of the address information stored by the second network-diversity-apparatus searching unit and acquires address information of a network diversity apparatus connected to the wireless base station from the wireless base station, and a second address-information notifying unit that notifies a network diversity apparatus connected to the wireless terminal station of the address information of the network diversity apparatus connected to the wireless base station acquired by the second address-information exchanging unit, and
- the downlink-data-frame copying and transmitting unit sets the address information, which is notified from the first address-information notifying unit, as a destination address of the downlink encapsulated data frame, and the uplink-data-frame copying and transmitting unit sets the address information, which is notified from the second address-information notifying unit, as a destination address of the uplink encapsulated data frame.
32: The communication system according to claim 30, wherein
- the downlink-data-frame copying and transmitting unit does not copy the downlink encapsulated data frame, sets a multicast address, which is used during multicast transmission to a wireless base station connected to the first network diversity apparatus, as a destination address of the downlink encapsulated data frame, and transmits the downlink encapsulated data frame, and
- the uplink-data-frame copying transmitting unit does not copy the uplink encapsulated data frame, sets a multicast address, which is used during multicast transmission to a wireless terminal station connected to the second network diversity apparatus, as a destination address of the uplink encapsulated data frame, and transmits the uplink encapsulated data frame.
33: A communication apparatus that is configured to be connected to a plurality of wireless base stations, transmits uplink encapsulated data frames received from the wireless base stations to destinations thereof, and transmits a downlink data frame received from a connected network to a destination terminal apparatus thereof through the wireless base stations, the communication apparatus comprising:
- a downlink-data-frame copying and transmitting unit that copies a downlink encapsulated data frame generated by encapsulating the downlink data frame received from the network and transmits downlink encapsulated data frames obtained by executing the copying processing to different wireless base stations, respectively; and
- an uplink-data-frame selecting and transmitting unit that selects, when a plurality of uplink encapsulated data frames having same content are received through different wireless base stations, respectively, any one of received uplink encapsulated data frames and transmits an uplink data frame generated by decapsulating selected uplink encapsulated data frame to a destination thereof.
34: The communication apparatus according to claim 33, further comprising a base-station-address storing unit that stores address information of a transmission source terminal apparatus included in an uplink data frame obtained by executing the decapsulation processing and address information of a wireless base station that transmits the uplink encapsulated data frame, wherein
- the downlink-data-frame copying and transmitting unit determines, when a downlink encapsulated data frame is copied, a destination address set in copied downlink encapsulated data frame based on a destination address of the downlink data frame and information stored by the base-station-address storing unit.
35: The communication apparatus according to claim 34, further comprising an address resolution protocol response packet generating unit that generates, when an address resolution protocol packet for performing path learning is received, a response packet to the address resolution protocol packet on behalf of a wireless base station connected to the first network diversity apparatus based on information stored by the base-station-address storing unit.
36: A communication apparatus that is configured to be connected to a plurality of wireless base stations and transmits uplink encapsulated data frames received from the wireless base stations and a downlink data frame received from a connected network to destinations thereof, the communication apparatus comprising:
- a downlink-data-frame copying and transmitting unit that copies a downlink encapsulated data frame generated by encapsulating a downlink data frame received from the network, sets media access control addresses, which are acquired in advance and allocated to a communication partner apparatus, as destination addresses of downlink encapsulated data frames obtained by executing the copying processing, sets virtual local area network identifiers of the wireless base stations, which are acquired in advance, in the downlink encapsulated data frames such that the downlink encapsulated data frames are transmitted through different wireless base stations, respectively, and transmits the downlink encapsulated data frames; and
- an uplink-data-frame selecting and transmitting unit that selects, when a plurality of uplink encapsulated data frames having same content are received through different wireless base stations, respectively, any one of received uplink encapsulated data frames and transmits an uplink data frame generated by decapsulating selected uplink encapsulated data frame to a destination thereof.
37: A communication apparatus that is configured to be connected to a plurality of wireless terminal stations and transmits downlink encapsulated data frames received from the wireless terminal stations and an uplink data frame received from a connected terminal apparatus to destinations thereof, the communication apparatus comprising:
- an uplink-data-frame copying and transmitting unit that copies an uplink encapsulated data frame generated by encapsulating an uplink data frame received from the terminal apparatus, sets media access control addresses, which are acquired in advance and allocated to a communication partner apparatus, as destination addresses of uplink encapsulated data frames obtained by executing the copying processing, sets virtual local area network identifiers of the wireless terminal stations, which are acquired in advance, in the uplink encapsulated data frames such that the uplink encapsulated data frames are transmitted through different wireless terminal stations, respectively, and transmits the uplink encapsulated data frames; and
- a downlink-data-frame selecting and transmitting unit that selects, when a plurality of downlink encapsulated data frames having same content are received through different wireless terminal stations, respectively, any one of received downlink encapsulated data frames and transmits a downlink data frame generated by decapsulating selected downlink encapsulated data frame to a destination thereof.
38: A wireless base station comprising:
- a wireless-terminal-station-address storing unit that stores address information of a transmission source terminal apparatus included in an uplink wireless data frame received from a wireless terminal station connected by wireless and address information of the wireless terminal station in association with each other; and
- a downlink-wireless-data-frame transmitting unit that transmits a downlink wireless data frame generated based on a downlink encapsulated data frame received from a network diversity apparatus to a wireless terminal station determined based on address information of a destination terminal apparatus included in the downlink data frame and information stored by the wireless-terminal-station-address storing unit.
39: A wireless base station comprising:
- a network-diversity-apparatus searching unit that broadcast-transmits, when the wireless base station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame;
- a wireless-terminal-station-address storing unit that stores address information of a transmission source terminal apparatus included in an uplink wireless data frame received from a wireless terminal station and address information of the wireless terminal station in association with each other;
- an uplink-encapsulated-data-frame transmitting unit that sets address information stored by the network-diversity-apparatus searching unit as a destination address of an uplink encapsulated data frame generated based on the uplink wireless data frame and transmits the uplink encapsulated data frame; and
- a downlink-wireless-data-frame transmitting unit that transmits a downlink wireless data frame generated based on a downlink encapsulated data frame received from the network diversity apparatus, which is connected to the own station, to a transmission destination wireless terminal station determined based on address information of a destination terminal apparatus included in the downlink data frame and information stored by the wireless-terminal-station-address storing unit.
40: A wireless terminal station comprising:
- a network-diversity-apparatus searching unit that broadcast-transmits, when the wireless terminal station is started, a network diversity apparatus search request frame for searching for a network diversity apparatus to be connected and stores address information of a network diversity apparatus that transmits a response frame to the network diversity apparatus search request frame and is disposed on a mobile on which the wireless terminal station is disposed; and
- a downlink-encapsulated-data-frame transmitting unit that sets address information stored by the network-diversity-apparatus searching unit as a destination address of a downlink encapsulated data frame generated based on a downlink wireless data frame received from a wireless base station and transmits the downlink encapsulated data frame.
Type: Application
Filed: Feb 6, 2007
Publication Date: Feb 25, 2010
Applicant: MITSUBISHI ELECTRIC CORPORATION (TOKYO)
Inventors: Hiroshi Hattori (Tokyo), Toshinori Hori (Tokyo), Toshiaki Tomisawa (Tokyo), Yoshihiko Shirokura (Tokyo)
Application Number: 12/524,168